1. Field of the Invention
This invention is related to a free-running-on, locking-off and tension directly indicated locking nut, which engages with a bolt with zero loading resistance, automatically produces loose resistant torque when fastened on a workpiece, and indicates whether the locking nut is fastened with the required axial tension by showing the change in the clearance between the body portion and the cap.
2. Description of the Prior Art
It has been found that the fastener composed of nut and bolt is an important element for the assembly of an object. The fastener is applicable in many fields, such as the steel structure of a building and even an household apparatus, and is an inevitable element for the engagement between workpieces or assembly of machine platforms. However, the engagement of the conventional nut and bolt will become loose or even disengaged when subjected to external force or other factors. Hence, it has been proposed to mount a packing between the nut and the workpiece in order to prevent this drawback. This is the best method for a static workpiece which might be dismantled in the future or which is a lightweight static member. Nevertheless, this method is not applicable to dynamic machines as the engagement between the nut and bolt will become loose when subjected to longtermed vibration. Similarly, this method is not applicable to the workpiece which will not be dismantled once secured. Thus, it has been proposed to insert fit a nylon member on the internal threads of the nut so as to strenghen the engagement between the nut and bolt. Nevertheless, this expedient is not applicable to a workpiece which is subjected to high temperature, acid or alkaline circumstance, as nylon will be melted at high temperature and dissolved in acid or alkaline circumstance, thereby rendering this expedient useless to strengthen the engagement between nuts and bolts. Furthermore, an expensive tension measuring device must be used in order to measure the tension required for locking the nut.
Therefore, it is an object of the present invention to provide a free-running-on, locking-off and tension directly indicated locking nut which can obviate and mitigate the above-mentioned drawbacks.